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The natural enemies hypothesis predicts that the abundance and diversity of antagonists such as predators and parasitoids of herbivores increases with the diversity of plants, which can lead to more effective top-down control of insect herbivores. However, although the hypothesis has received large support in agricultural systems, fewer studies have been conducted in forest ecosystems and a comprehensive synthesis of previous research is still lacking.We conducted a meta-analysis of 65 publications comparing the diversity, abundance or activity of various groups of natural enemies (including birds, bats, spiders and insect parasitoids) in pure vs. mixed forest stands. We tested the effects of forest biome, natural enemy taxon and type of study (managed vs experimental forest).We found a significant positive effect of forest tree diversity on natural enemy abundance and diversity but not on their activity. The effect of tree diversity on natural enemies was stronger towards lower latitudes but was not contingent on the natural enemy taxon level.Overall, our study contributes toward a better understanding of the “natural enemies hypothesis” in forest systems and provides new insights about the mechanisms involved. Furthermore, we outline potential avenues for strengthening forest resistance to the growing threat of herbivorous insects.

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International audience; h i g h l i g h t s The influence of the PTL properties on the electrolyzer performance was investigated. Optimal performance was obtained for an average pore size of 10 mm and porosity of 31%. The pressure influence on the mass transport limitations was proved. Current density heterogeneities were observed with a segmented PEM electrolyzer. A new model for the constriction resistance in the catalyst layer was developed. Porous transport layer Segmented electrolyzer Mass transport limitations a b s t r a c t A titanium Porous Transport Layer (PTL) is usually used at the anode side of PEM water electrolyzers to ensure both the gas/water transport and the electric charges transfer. In this paper, four different sintered Ti powder PTLs were characterized to determine some properties, such as the pore size distribution, the porosity, and the permeability. Their influence on the electrolysis performance was investigated by using a 30 cm 2 segmented cell which allowed measuring the current density distribution, while controlling temperature and pressure conditions. For a better understanding, in-situ techniques such as the Polarization Curves and the Electrochemical Impedance Spectroscopy (EIS) were used. A local characterization of mass transport limitations caused by oxygen saturation was carried out, paying special attention to the pressure influence when using a PTL with very small pores. The results showed that current density heterogeneities can be explained by microstructure changes along the PTL. The optimal geometric characteristics of the PTL depend not only on the operating conditions such as current density, pressure, and temperature but also on the catalyst layer properties. A new model for the constriction resistance between the catalyst layer and the PTL was proposed. ScienceDirect j ou rnal h ome pag e: www.elsevier.com/loca te/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 5 (2 0 2 0) 8 0 9 4 e8 1 0 6

International audience; The water electro-osmotic drag coefficient of a cation _ Kdrag(cation)_ is defined as the number of water molecules which is dragged by a cation when it goes through a membrane at equilibrium state (i.e. in the absence of water concentration gradient within membrane). This coefficient is one of the key elements for modeling the water balance through Nafion membrane in a proton Exchange membrane Fuel cell (PEMFC). In this work, we have applied the method of electrophoresis NMR (ENMR) to determine the coefficient of electro-osmotic drag (Kdrag) within Nafion prepared in different cationic forms (H+, Na+ and K+). Applying, in all cases, the same method for determining Kdrag of Nafion membrane in many cationic forms should be appropriate in order to apprehend the mechanisms of water transport which occur in this membrane. This method consists in measuring the phase of the water NMR signal under the application of an electric current in a diffusion-like experiment, this phase being proportional to the flux of water within Nafion. The results show that the electro-osmotic coefficients of water within Nafion depend on the type of counter-cation and on the water content of Nafion. Due to proton lability, the electro-osmotic drag coefficient of water within Nafion in the acid form (Kdrag(H+)) is the lowest among the three studied cationic forms. In a dehydrated state of Nafion, the Kdrag(H+) is lower than 1, suggesting here that the hopping mechanism is favored. In the case of Nafion in sodium and potassium forms, Kdrag of these cations is always higher than 1. This can be rationalized by the vehicular mechanism and also by a strong interaction between the water solvation of the cation and the cation itself.

Resume Le phenomene des NPS (nouvelles substances psychoactives) emerge depuis quelques annees en France et en Europe. De nouvelles molecules, variations structurelles autour d’un noyau psychoactif connu, apparaissent regulierement sur Internet. Les laboratoires d’analyse saisis par les services d’enquete et la justice doivent les identifier pour determiner leur statut legal. Ils sont alors confrontes a des difficultes techniques de taille. Cet article decrit plusieurs cas rencontres au laboratoire de police scientifique de Lyon entre fin 2014 et 2015, et pour lesquels des confirmations structurales par resonance magnetique nucleaire se sont averees necessaires, mettant en evidence 4-fluoroamphetamine, MDMB-CHMICA, 3-chloromethcathinone et MDMB-FUBINACA. Il dresse en outre un portrait du marche et des usagers.

International audience; We address the problem of measuring accurately and as quickly as possible a self-diffusion coefficient by the so-called pulsed gradient stimulated echo experiment or, equivalently, by using a sequence involving radio-frequency field gradients. The discussion deals with the smallest diffusion coefficient which can be measured with a reasonable accuracy, possibly taking into account the values of longitudinal and transverse relaxation times along with the nature of gradients. It is shown theoretically and experimentally that the diffusion coefficient can be measured accurately via only two experiments provided that the ratio of the signal amplitudes lies in the range 0.2–0.6.

Introduction La plupart des genes impliques dans les mouvements anormaux (MA) ne sont pas explores en routine. De plus, l’approche diagnostique peut etre difficile du fait d’une heterogeneite genetique et phenotypique. Objectifs L’objectif de notre etude est de developper une technique de sequencage haut-debit cible de 127 genes impliques dans les MA. Patients et methodes Au total, 127 genes impliques ou candidats dans les MA ont ete cibles en utilisant des sondes ADN biotinylees. Parmi les patients, 387 souffrant de formes precoces, atypiques ou familiales de MA et issus essentiellement de 25 centres francais ont ete selectionnes. Les echantillons ont ete prepares et sequences en utilisant des techniques de sequencage nouvelle generation. Les donnees ont ete traitees a l’aide d’outils bioinformatiques avant d’etre discutees collegialement par les geneticiens et les cliniciens. Resultats Des mutations causales probables ont ete identifiees chez 83/387 patients (21,5 %). Le rendement diagnostique etait de 24 % (45 cas resolus) pour les patients presentant comme principal symptome un syndrome parkinsonien, 15 % pour la dystonie (19 cas resolus), 30 % une choree (7 cas resolus), 28 % des MA paroxystiques (5 cas resolus), 60 % une paraplegie spastique (3 cas resolus) et 20 % un syndrome cerebelleux (3 cas resolus). Discussion Plusieurs variants ont ete retrouves dans PLA2G6, VPS13A, ATP13A2, DNAJC13, GCH1, ADCY5, AP4B1, DJ-1, GLRA1, VPS35 et WDR45, suggerant qu’ils sont moins rares qu’actuellement admis. Nos resultats confortent l’implication de DNAJC13, HTRA2 dans les MA mais ne confirment pas l’implication d’autres genes candidats (ANO3, CIZ1, GIGYF2) et plaident pour un spectre plus large de PRKRA, PARK2 et PRRT2. Conclusion Le sequencage cible semble etre un outil diagnostique efficace dans le domaine des MA, et contribue a une meilleure definition des spectres phenotypiques et comprehension de la contribution des differents genes impliques.

This paper presents the global process that was adopted for modelling complex systems involving several branches of engineering, using the Bond Graph method. The applications of the model obtained with such a process can be the C.A.D. (Computer-Aided Design) or the simulation of the dynamic behaviour of a system used for developing complex control/command algorithms. This process will be illustrated by two applications. The first application deals with a knowledge model of a tractor and a semi-trailer, which allows the study of its behaviour by simulation. The second application is the design of one of its sub-systems: a new servovalve used for driving the safety components of this vehicle.

This article presents the modelling of a motor vehicle and its braking system (Fig. 1). The system to be modelled consists of the vehicle with all the suspension elements-wheel, tyre and wheel-road interface. The model must account for the behaviour of the whole system according to the longitudinal and vertical axes when the wheel is decelerated. The mass of the quarter vehicle on each wheel has to be adaptative during the braking phase in order to model the mass transfer. So, we have developed a 15th order knowledge model from the functioning equations for CAD and a 2nd order representation model for control which was obtained through identification. The knowledge model has been introduced using our “Prouesse” Bond Graph Tool. We are now developing the complete model of a semi-trailer.

Resume Notre but est d'etudier precisement les transferts de chaleur et de masse dans les milieux poreux non-satures ou dans les materiaux a changement de phase. Nous proposons un montage experimental dans une geometrie classique (cylindre de petit diametre par rapport a la hauteur a temperature imposee a la base et au sommet, isole lateralement), permettant une mesure d'absorption gammametrique en fonction de la hauteur. La principale difficulte est liee a l'isolation laterale qui doit etre efficace aussi bien en regime transitoire qu'en regime permanent. La principale originalite est de mesurer le flux de chaleur a la base et au sommet du cylindre, en permettant ainsi de tester l'isolation thermique plus particulierement en regime permanent. Nous presentons enfin les difficultes de mise au point ainsi que les resultats obtenus.

Resume On etudie, en regime permanent, l'ebullition dans une couche poreuse horizontale. La face inferieure impermeable est chauffee a flux constant, tandis que la face superieure saturee par un fluide (eau) a pression ambiante est refroidie a temperature constante. Par rapport aux modeles precedemment publies et pour se rapprocher des conditions observables experimentalement, on examine successivement l'influence de la conduction en zone diphasique, des pertes de chaleur laterales et de la prise en compte de gaz incondensables (air) contenus dans le milieu.